ABRADING WHEEL WITH SINTERED METAL CORE
Article and method of making an abrading wheel having a sintered metal core and radially inward openings having curved inner edges to reduce stress in operation and to improve the ability of the wheel to clear residue from the wheel during operation.
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The present invention relates to abrading wheels of the type used to finish the surface of a rubber product to form a desired surface smoothness. This type of abrading wheel may be used in the retreading of tires, for example, as well as in finishing the surface of rubber rollers to a predetermined tolerance.
BACKGROUND OF THE INVENTIONIn the past, abrading wheels of this type have generally had a core of uniform thickness and diameter, to form the general shape of a disc, with tungsten carbide grit on the outer peripheral surface.
It has been found desirable to provide radial grooves or openings in the finished wheel. These grooves act as regions of accumulation for the material being removed and facilitate release of the material from the abrading wheel. Without the radial grooves or openings, the grit surface would tend to accumulate material and become packed with “dust”, thus reducing its ability to remove further material from the work piece, by clogging the interstices of the grit surface.
In the past, the radial openings have been formed by machining through the peripheral surface (or rim) of the disc-shaped wheel and into the central portion of the core. This is an expensive process; six radial grooves typically are formed in each abrading wheel. Moreover, the cutting process left sharp corners which provided regions for accumulating the residue of the abrading process, and created regions of stress in the wheel.
SUMMARY OF THE INVENTIONAn abrading wheel has a core made of sintered metal. The core may be in the general form of a disc having a plurality of peripheral sectors of equal angular extension. Adjacent sectors are separated by a generally U-shaped radial opening having a smoothly curved inner, central surface to avoid accumulation of the material removed from a work piece while reducing stress on the smooth openings, and to reduce stress in the core. The shape of the radial openings also promotes the flow of air through the openings to remove any accumulated residue.
The use of powder metal technology to manufacture the core has many advantages, including: lower manufacturing cost because there is no need to machine the piece; the ability to maintain close dimensional tolerances without machining; and adaptability to a wide variety of alloy systems to accommodate different applications.
Referring first to
Referring first to
The core 10 has first and second identical sides, as mentioned. The core 10 includes a central portion 11 of a relatively larger thickness (see
An opening 19 (
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There are 6 radial openings 20 in
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Referring to
(1) A core as shown and described is provided, as illustrated in block 32;
(2) In block 34, an adhesive linking agent such as polyvinyl alcohol is applied to the outer perimeter surface of the individual segments of the sintered metal core 10;
(3) Next, in block 36, the tungsten carbide grit 30 is applied over the binder (the grit may be poured as the core is rotated);
(4) Next, in block 38, brazing material in powder form (which may be nickel or copper) is applied to the entire perimeter surface, including the tungsten carbide grit which is adhesively secured to the perimeter; and
(5) The entire product is then heated, in block 40 in an oven at approximately 2000° F. for approximately ten minutes to melt the brazing powder which, when cooled, secures the tungsten carbide grit 30 to the outer surface of the individual segments 28A-28F.
By forming the radial openings 20 as described, that is, with an increasing width (circumferential) in proceeding radially inward of the core 10, and having the innermost ends of the two straight edge sidewalls, 23, 24 joined by a smoothly curved innermost portion (25 in
Having thus disclosed in detail the preferred embodiment of the invention, persons skilled in the art will be able to modify the certain of the materials, structure and process steps which have been disclosed herein, while continuing to practice the principle in the inventions; and it is, therefore, intended that all such modifications and substitutions be covered as they are embraced within the spirit and scope of the appended claims.
Claims
1. An abrading wheel comprising:
- a core of sintered metal having a plurality of equally angularly spaced openings extending radially inward of the periphery of the core, each of said openings having a curved inner edge spaced outwardly of a center of said core;
- said openings defining a plurality of peripheral sectors of substantially equal circumferential extension; and
- tungsten carbide grit fixed to the outer surface of each of said sectors.
2. The abrading wheel of claim 1 wherein each of said radially extending openings has first and second side surfaces extending from the perimeter of said core to said curved inner edge.
3. The abrading wheel of claim 1 wherein said side surfaces for each opening are spaced increasingly further apart proceeding from the periphery toward an associated inner curved surface.
4. A method of making an abrading wheel comprising:
- providing a core of sintered metal and having a plurality of openings, each extending inwardly of the periphery and having a smoothly curved inner edge, said openings defining a plurality of sectors of approximately equal angular extension; each sector having a circumferentially extending outer surface;
- applying a binding agent to the outer circumferential surfaces of said sectors;
- thereafter applying tungsten carbide grit to said outer circumferential surfaces;
- thereafter, applying a brazing powder to said core and grit; and
- thereafter heating said core, grit and powder to approximately at least 2000° F.
5. The method of claim 4 wherein said step of heating is applied for approximately ten minutes at 2000° F. or greater.
Type: Application
Filed: Dec 21, 2007
Publication Date: Jun 25, 2009
Patent Grant number: 7972200
Applicant: B & J MANUFACTURING COMPANY (Glenwood, IL)
Inventor: Charles K. Stanfield (Crete, IL)
Application Number: 11/962,782
International Classification: B24B 5/00 (20060101); B24D 11/00 (20060101);